1. Field of the Invention
The present invention relates to telephonic apparatus generally and more particularly to a remote-telemetry unit for condition monitoring and reporting, the unit having means by which the unit may be poled.
2. Description of the Prior Art
Heretofore, providing maintenance for office equipment has been an expensive, hit-or-miss proposition. Obviously, routine maintenance may reduce the likelihood of extensive downtime; yet, unnecessary maintenance is expensive. But, absent indices of the condition of a piece of office equipment, it is very difficult to schedule preventative maintenance therefor. Even scheduling meaningful periodic maintenance is difficult absent wear indices, such as, for example, the number of sheets of paper used in a photocopy machine during a particular period of time, especially where the level of machine usage is not constant. And, when a piece of equipment does go down, prompt detection and notification thereof is important to minimize downtime.
A combined burglar-alarm and remote-telemetry unit of prior-art type employs a microcomputer for monitoring a number of switches and sensors and a modem driven by the microcomputer for reporting certain conditions over a telephone line to a central location. The modem includes a direct access arrangement (DAA) for selectively coupling the unit to the telephone line, circuitry for developing suitable dual-tone multi-frequency (DTMF) (touch-tone) tones for dialling, additional circuitry for developing originate tones, circuitry for recognizing answer tones (both of the type which are compatible with Bell 103 protocol) and a power supply for developing unit operating power from a 110-volt power line (system).
The above-mentioned prior-art-type unit is disadvantageous in that the circuitry for developing the dialing tones, for developing the originate tones and for recognizing the answer tones is relatively complex and expensive. Additionally, the unit lacks means by which the unit may ascertain the time and date to permit the unit to determine the number of events (conditions) which occur within a given period of time and to permit the unit to report its status at predetermined times. Also lacking is means permitting the unit to answer telephone calls to be poled to ascertain its status and that of the various switches and sensors monitored thereby. Finally, 110-volt power lines are, oftentimes, not conveniently available either to furnish primary or backup power.